Windows Azure Files allows VMs in a Windows Azure Data Center to mount a shared file system using the SMB protocol. These VMs will then be able to access the file system using standard Windows file APIs (CreateFile, ReadFile, WriteFile, etc). Many VMs (or PaaS roles) can attach to these file systems concurrently, allowing you to share persistent data easily between various roles and instances. In addition to accessing your files through the Windows file APIs, you can access your data using the file REST API, which is similar to the familiar blob interface.

Signing up

At the time of writing, the Azure Files service is in preview and therefore must be activated for your account. You can do this by going to the the preview page and clicking “Try it”.

During the activation, you are asked which subscription you wish to apply it to. Then it is a waiting game.

The activation took 21 days! This process is obviously subject to change when the service moves out of beta.

The Scenario

In my case, I want to create a shared disk that is accessible from two VMs.

Creating a storage account

Once Azure Files is activated on your account any new Storage account you create will have it enabled automatically. At the time of writing, I am not aware of a way to retroactively enable Azure Files on an existing storage account.

Again, make sure you replace the placeholders with the appropriate values from above. This command is the standard command for mapping a network drive. Only this time, the drive is in Azure.

Do this on all the machines you wish to have access.

You can now access this drive just like any other network drive from This PC in Windows.

Performance

Obviously, the next step is to test performance. The test is obviously restricted by the bandwidth on the machine, so I decided to use the Azure VM I created earlier. As we all know, Azure datacenters have more bandwidth than god, but I must admit, the results below were quite surprising.

The transfer peaked at 60 MB/Sec write and 67 MB/sec read. That is pretty impressive! I decided to watch the network traffic whilst this was happening and took a snapshot.

As you can see, at the point in time the screenshot was taken, there was 557Mbps being received via the network adapter. Seriously fast!

Note: The limiting factor of any speed test you do yourself, will be your internet connection. The above was so fast because it was performed on an Azure VM.

Conclusion

Azure Files is a fantastic addition to the Azure family and is a feature that I can certainly think of some uses for.